1. Field of the Invention
The present invention relates to a liquid ejection apparatus and a sensor unit.
2. Description of the Related Art
In a liquid ejection apparatus which applies a liquid to a medium by ejecting the liquid from an ejection port of a liquid ejection head and conveying the medium while moving a carriage carrying the liquid ejection head, the structure has been known in which a sensor is attached as a sensor unit to the carriage.
Japanese Patent Laid-Open No. 2007-62222 discloses the structure in which an optical element (sensor) composed of a light emitting element and a light receiving element is attached to a carriage so that light emitted from the light emitting element to a medium and reflected by the medium is received at the light receiving element.
When ink droplets are ejected from the ejection port of the liquid ejection head, mist may be generated along with ink droplets applied to the medium. Adhesion of mist to the light emitting element or the light receiving element may induce change in the amount of light emitted from the light emitting element, and change in the amount of light received at the light receiving element, thereby deteriorating detection accuracy of the sensor.